What was found
BOTH HF 2 FREQUENCY INDICATORS DISPLAY FAIL. GROUNDED - YES. VERIIFIED "FAIL" ON BOTH HF #2 WINDOW, REPLACED NEW HF #2 TRANSCEIVER & INSTALLATION TEST PASSED B737-9 AMM 23-11-21/401, BOTH HF#1 & HF#2 FAILED ON SYSTEM TEST AMM 23-11-00-730-801 3F(1)(C)(4)(A) UNABLE TO TRANSMIT OR RECEIVE FROM SFO-ARINC RADIO STATION, TRANSMITTING & RECEIVING FROM AIRCRAFT TO AIRCAFT AT SEA ARE FINE, BOTH HF#1 & HF#2 INOP, REPLACED MEL 23-11-01B TO NEW MEL 23-11-01A. REF L/P 60466539, FLIGHT CREW PERFORMED SUCCESSFUL HF1 & HF2 RADIO CHECK WITH SFO RADIO STATION, CLEARS MEL 23-11-01A.